diff options
| author | Al Viro <viro@zeniv.linux.org.uk> | 2014-06-12 08:27:11 +0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2014-06-12 08:28:09 +0400 |
| commit | 9c1d5284c79fea050f115eadeec1dd1758e5c630 (patch) | |
| tree | 4d16fd5aad7ff4931e985c0128c5747f23561f8a /block/blk-cgroup.c | |
| parent | 5f073850602084fbcbb987948ff3e70ae273f7d2 (diff) | |
| parent | 9f12600fe425bc28f0ccba034a77783c09c15af4 (diff) | |
| download | linux-9c1d5284c79fea050f115eadeec1dd1758e5c630.tar.xz | |
Merge commit '9f12600fe425bc28f0ccba034a77783c09c15af4' into for-linus
Backmerge of dcache.c changes from mainline. It's that, or complete
rebase...
Conflicts:
fs/splice.c
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'block/blk-cgroup.c')
| -rw-r--r-- | block/blk-cgroup.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index e4a4145926f6..1039fb9ff5f5 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -451,7 +451,20 @@ static int blkcg_reset_stats(struct cgroup_subsys_state *css, struct blkcg_gq *blkg; int i; - mutex_lock(&blkcg_pol_mutex); + /* + * XXX: We invoke cgroup_add/rm_cftypes() under blkcg_pol_mutex + * which ends up putting cgroup's internal cgroup_tree_mutex under + * it; however, cgroup_tree_mutex is nested above cgroup file + * active protection and grabbing blkcg_pol_mutex from a cgroup + * file operation creates a possible circular dependency. cgroup + * internal locking is planned to go through further simplification + * and this issue should go away soon. For now, let's trylock + * blkcg_pol_mutex and restart the write on failure. + * + * http://lkml.kernel.org/g/5363C04B.4010400@oracle.com + */ + if (!mutex_trylock(&blkcg_pol_mutex)) + return restart_syscall(); spin_lock_irq(&blkcg->lock); /* |